【摘要】 本文利用国产 FJ-353双道液体闪烁计数器,研究了低水平~3H 的测量方法。对该仪器采用了屏蔽、铜光导等改进措施,选用了适合于低水平测量的闪烁体系及聚四氟乙烯测量瓶等条件,使该仪器在用作~3H 的低水平测量时,本底可降至5.5±0.3cpm。环境样品经过燃烧和电解浓集处理之后,在计数效率为19.7%,样品量为2ml,测量时间为100分钟和置信度为95%时,~3H 的最小可探测浓度;水中为25T.U.,食品为8pCi/kg。本方法可应用于环境中~3H 放射性水平的调查。更多还原

【Abstract】 A low-level ~3H counting method has been studied by usinga FJ-353 double-channel liquid scintillation counter with a shield and a copperphotocon.The background counts could be reduced to 5.5±0.3 cpm when thescintillation system and teflon vials were properly adopted.In combinationwith a sample enrichment technique,the minimal measurable concentrationsfor tritium were 25 T.U.in water and 8 pCi/kg in food with the sample vo-lume of 2 ml,when the counting efficiency was 19.7% the confidence 95%and the counting time 100 min.It is suggested that this method can be usedfor investigating the content of ~3H in the environment.更多还原